Air conditioning apparatus



Aug. 15, 1939. J. H. SIMPSON AIR CONDITIONING LPPARATUS 3 Sheets-Sheet 1 Filed Oct. 30, 1931 EEE LEE-E-E fiihaaa-..

I l l I I 1 1 I l l l l 15, 1939. J. H. SIMPSON ,169,435

- AIR conni'rroume APPARATUS Filed Oct. 30, 1.937 SSheets-Sheet 2 Aug. 15, 1939. J.'H. SIMPSON AIR GONDIT IONING APPARATUS File d Odt. :50, 1937 s Sheets-Sheet s Patented Aug. 15, 1939 STATES AIR CONDITIONING srrannrcs' Jerry H. Simpson, Winston-Salem, N. Q" gnor to The Bahnson Company, Winston-Salem, N. 0., a. corporation of North Caro Application October 30,

8 Claims.

This invention relates to air conditioning apparatus and parts thereof, and more particularly to an air conditioning system for use in shops or mills in which the air normally carries a substantial quantity of dust, lint and the like.

Lint and dust of the sizing material used on cotton thread are always present in the air in cotton spinning and weaving mills, and this dust content may-be so high that it is impossible to' see clearly from one end to the other of a long weaving room. A relatively high humidity must be maintained-and the mixture of size dust and lint tends to adhere to surfaces which it contacts as the moist air is circulated in the mill. It has been proposed to remove the size dust and lint by fiat screen filters in the air circulating system, but the quantity and character of the material are such that the filters must be cleaned every few hours. The material is readily filtered from the air stream but the cleaning of the filters has presented a diilicult problem which, up to the present, has necessitated a manual cleaning.

An object of the present invention is to provide air conditioning apparatus including filters of novel design for removing dust, lint and the like from the air. An object is to provide an air conditioning system of the type in which the room air is maintained in continuous circulation during use of the room, and which includes a selfcleaning filter for removing dust and lint from the air. More specifically, objects are to provide air filters and /or air conditioning systems including air filters, in which the filter is of the cylindrical screen type and includes elements for periodically or continuously removing dust and lint accumulations irom the filter. A further object is to provide apparatus including a rotatable screen filter, and filter cleaning apparatus for removing the collected felt of dust and lint .upon a rotation or partial rotation of the screen. Another object a is to provide a filter section for incorporation in the duct of an air conditioning system, the filter section including a casing housing a self-cleaning filter for removing dust and lint from the air before it passes the air conditioning elements within the duct.

These and other objects and advantages of the invention" will be apparent from the following specification when taken with the accompanying drawings in which:

Fig.1 is a fragmentary plan view of an embodiment of the invention which includes one or more ducts for circulating, humidifylng and/ore heating the air, and a self-cleaning filter-for re-x oi:-the,.prior ;sys alh veincluded a seli-cleanmoving dust and lint from the air;

1937, Serial No. l'?l,9'i2 (Cl. Edit-52) Fig. 2 is a fragmentary side elevation of the same;

Figs. 3 and d are end views, from the inlet and outlet end, respectively, of the filter unit;

Fig. 5 is a sectional view through the filter unit, 6 the filter and cleaning apparatus being shown in elevation; and

Fig. 6 is an enlarged fragmentary end elevation of the cleaning apparatus and a portion of the rotatable filter screen.

In the drawings, the reference numeral 8 identifies a part of an outside wall into which a mixing chamber 2 is built; the chamber having a room opening and an exterior opening t for admitting room air and outside air, respectively, to 15 the mixing chamber. Interconnected louvers or dampers 5, d are arranged in openings 3, t, respectively, for regulating the mixture of room and outside air, and a screen i is placed. across the exterior opening tl. The chamber 2 opens 20 into the casing ll of a filter unit which, in turn, opens into the casing section Q that houses a tubular heater ill. The next casing section II of the air duct houses a humidifier element that is preferably of the type including a circulating 25 fan it, motor it and rotating disk humidifier M.

A heater and humidifier assembly such as described in the patent to Frederic F. Bahnson, No. 1,745,239, is. shown in the drawings but the exact construction of these parts is not an essential 30 feature of this invention.

lihe casing it opens into the tapered distributing duct it that has a plurality of laterally directed openings it along one or both sides. The arrangement of the openings it depends upon 35 the particular air circulation that is to be set up in the room. The duct it will extend approxi- .m ately to the center line of the room, just below the ceiling, and will haveoutlem along one side when the room air is circulated his. single closed 40 circuit, there being one or more similar ducts at the opposite side of the room with the outlets opening in the opposite direction. Openings l6 will be provided at both sides of the duct l5 when the room airis circulated in two closed loops at opposite sides of the duct. The relative quantities of recirculated room air and of fresh air are regulated by the adjustment of the dampers 5, 5, and this regulation is preferably automatic butthe particular control is not a part of the present invention. This general arrangement ,for conditioning air lay-circulation through one or more-ducts vwithinzthe room is known, but none 2 ing filter unit for removing dust and lint from the air stream.

According to the present invention, the circulating air is filtered before it reaches the heater and /or humidifier of the air conditioning system,

' and the collected material is removed continuous- 1y or periodically from the filter. The casing I of the filter includes end frames I1, I. and a circumferential wall It Supports 20 on the frame I! carry the motor 2| which rotates theshaft 22. A journal 23 for the other end of the shaft is carried by a skeleton support II on the frame i8 at the outlet end of the casing 8. A solid disk or plate 25 at the inlet end and'a spoked wheel "20 at the outlet end support a rotatable .screen filter 21 that may be cylindrical, as shown, or conical. A sealing ring 28 of tape or thin leather is mounted on the outlet endwall of the casing 8 and overliesLthe outlet end of the rotatable screen 21 to prevent the short circuiting of air aroundthe filter. A domed 0r streamlined shell 29 is preferably arranged about the motor ii to shield the same from the dust and lint of the entering air stream and-to guide the air stream smoothly into the space between the casing wall II and the filter screen 21. The air current established by fan i2 enters the casing 8 around the screen 21, passes radially through the screen, and leaves the casing axially of and from withinthe filter screen.

The screen mesh is not fine enough tostop all of the size dust but the lint is stopped by the,

screen and forms a filter mat that will remove even the finest particles of dust. The resistance to air fiow increases as the felted mass of lint and size dust builds up on the filterscreen, and this felt must be removed either continuously or at intervals during the day. The timing for one rotation of the screen, either continuously or intermittently, will depend upon the amount and y nature of the removed material.

Rotary brushes, scrapers and rapping devices cannot be employed for automatically removing the felted mass of lint and'dust. A clean rotary brush will remove the felt, but the mass immediately clogs the brush and prevents any further cleaning action. Scrapers and'devices for rapping the screen are not eil'ective. whether or not a shield is used to block the air stream from the part which is to be cleaned. Rotary brushes and rapping devices tend to loosen some of the dust caught in the felted mass accumulated on the filter screen, permitting such dust to pass through the screen, whilescrapers have been observed 150.

produce a similar result inasomewhat less degree. The present cleaning means was developed to remove, with the least possible disturbance, the accumulation of lint and dust on the screen, .and even with this construction the screen must revolve slowly-with a surface'speed of only a few feet per minute. In certain applications where the dust is fine, the fan must be stopped while the screen is moving, whichresult is readily accomplished by controlling motor II and the motor driving fan if by a double throw switch.

We have found that the felted mat M of lint, sizing dust and other particles may be readily removed byfirst rubbing and rolling the. felted mass into strands or bats., Thepressure and rolling motion for forming the strands or bats B are obtained by yieldingly holding the flexible pressure band- III against-a longitudinal strip of the screen cylinder 21. above and in advance, as viewed in the direction of rotation, of the bottom portion of the cylinder. The upper edge of the double thickness band '30 of relatively smooth cloth is formed as a loop 3| for supporting the band on a rod 32 that'is mounted on arms 33 secured to the,end-frames i1, ii. A strip 34 of smooth flexible material, such as glazed leather, oilcloth or a sheet of cellulose acetate between the lower edges of the band. '30 and extends over a rod 35 that is supported by posts it on the end frames. A metal bar 34' on the strip 34 supplies the pressure for holding'the band It against the surface of the screen cylinder;- The band 30, being doublesurfaced,'may be reversed-when one side is worn. A dust box 31 dependsbelow the shell I! of casing 8, and its hinged bottomdoor 38 has a ring 39 for engagement by a hooked rod when the box is to be opened to drop the collected material into a bag. U

The band 30 is relatively smooth, to prevent the lint from adhering to it, but it oflers a substantial resistance to the movement of the felted material M between the screen 21 and the band when the screen is rotated,-'and the material is thus rolled and twisted into bats B that do not adhere to the screen 21; The bats B thus slide freely over the smooth lower portion 34 of the band and dropinto the dust box when the strand is relieved from the pressure of the band 30.

The working of the f'elted mass into strands or bats will release some of the finer sizing dust from the-m'ass and the band 30 is therefore of fine mesh to have a high resistance to air fiow through the band. This yis particularlydesirable when the screen is rotated continuously at slow speed. The fine dust which passes the filter screen 'during cleaning will notbe objectionable when the several sections of the casings are designed; as shown, to decrease the effective crosssection of the air stream as'it passes from the filter to the duct outlets. The air stream is thus continuously accelerated and the small content of dust. will beheld in suspension. A

It is preferable, however, to clean the screen at intervals and by fractions of a revolution, for example a quarter turn. If conditions are such that the entire screen surface should be cleaned every two hours, the motor 2| can be energized for two or three minutes, at half-hour intervals, to

ing operation may be performed continuously or in widely different time cycles in accordance with the particular conditions encountered.

I claim:

1. In an air conditioning-system a filter 'comprising a rotatable screen,-'means for rotating the screen, and a flexible cleaning member yieldingly contacting a portion of the screen at the air inlet side to roll a felted accumulation of removed material into bats.

2. In an air conditioning system,-the invention as, claimed in claim 1, where said rotatable screen comprises a shaft, axially spaced screen supports of solid and, skeleton form on said shaft, 7

and a filter screen coaxial with said shaft and carried by said'screen supports.

3. man air conditioning system, a filter section for incorporation in an air duct, said section comprising a casing, a shaft approximately coaxial with said casing, a solid disk on the end of the shaft adjacent the casing inlet end, a

skeleton supportingring on the other end of the shaft, a screen extending between the peripheries of the disk and ring, means restricting the flow of air through the outlet end of the casing to that which passes through said screen, a flexible pressure band, means yieldingly holding said band against a longitudinal strip of the screen above and in advance, as viewed in the direction of rotation of the screen, of the bottom of the screen, and means for rotating said shaft and the screen mounted thereon.

4.,A filter section as claimed in claim 3, in combination with a dust box extending along and below the casingof the filter section, and a hinged I bottom door for s'aid dust box.

5. A filter for use in an air conditioning system,

said filter comprising a rotatable shaft carrying I of said screen, a flexible pressure band contactlog said screen to roll felted material accumulated thereon into bats, and motor means for rotating said shaft and the screen carried thereby.

6. A filter as claimed in claim 5, in combination with means for periodically energizing said motor means to effect a partial revolution of the shaft and screen.

'Z.'In apparatus for removing lint, dust and the like from air, a shaft having axially spaced screen supports, a screen coaxial with said shaft and connected between the peripheries of said screen supports, one of said supports being aper tured to permit air flow therethrough, means preventing air from entering axially of the screen at the other support, means for rotating the shaft and the screen supported thereon, a pressure band extending along and contacting the screen, and means yieldingly holding said band -against said screen, whereby accumulations of felted material on the screen will be rolled into strands when said screen is rotated.

8. Apparatus as claimed in claim 7, wherein said band. comprises a doubled flexible sheet having a. loop along one edge, a strip of smooth flexible material secured at one edge to the second edge of said doubled sheet, and means weighting the other edge of said strip; and said holding means comprises a rod extending through the 

